Design and validation of a 2D CFD model of the airflow produced by an airblast sprayer during pesticide treatments of citrus

Salcedo, Ramón; Granell, R.; Palau, Gladys; Vallet, A.; Garcerá, Cruz; Chueca, Patricia; Moltó, Enrique

doi:10.1016/j.compag.2015.06.005

Cited by 15 publications

(16 citation statements)

References 30 publications

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“…La precisión fue de 1.5 % con una resolución de 0, 01 m/s. En cada punto se registraron durante un minuto las tres componentes de la velocidad, margen de tiempo lo suficientemente largo para que las velocidades captadas representen el régimen estacionario en estas condiciones (Salcedo et al, 2015).…”

Section: Obtención De Los Datos Experimentalesunclassified

“…Existen publicaciones donde se aborda esta cuestión de forma descriptiva acompañada de ejemplos (Celik et al, 2008). En el caso de estudio, dicho análisis fue llevado a cabo en Salcedo et al (2015), por lo que, en coherencia con dicho trabajo, se recomienda adoptar directamente celdas de 4 cm de lado en la entrada de aire en el modelo y la zona de losárboles. En esa zona las celdas siguen una distribución uniforme.…”

Section: Malladounclassified

“…El aire para este modelo se consideró incompresible, hipótesis asumible en flujos por debajo del umbral de 100 m/s (Salcedo et al, 2015), isotérmico y newtoniano. Como datos de entrada, se emplearon las velocidades experimentales registradas en los postes A y B.…”

Section: Definición De Variables Y Parámetrosunclassified

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Introduciendo la dinámica de fluidos computacional en el análisis de flujos en medio poroso

Salcedo

Bayón

Chueca

2017

Model. Sci. Educ. Learn.

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Introduciendo la dinámica de fluidos computacional en el análisis de flujos en medio poroso Introducing computational fluid dynamics in the analysis of porous medium flows AbstractEste trabajo presenta una introducción a la modelización con Dinámica de Fluidos Computacional (CFD) de un fluido atravesando un medio poroso. Para ello, se propone un caso práctico mediante la simulación de un flujo de aire producido por el ventilador de un pulverizador hidráulico asistido por aire que atraviesa un medio poroso (la vegetación). El trabajo consiste en dotar de las herramientas necesarias para configurar un modelo CFD para, posteriormente, ajustar la resistencia de la porosidad al paso de la corriente usando datos experimentales. El ajuste contempla tres escenarios: uno, considerando sólo pérdi-das inerciales iguales entre los diferentes cuerpos porosos, dos, considerando dichas pérdidas inerciales más las pérdidas viscosas y, tres, considerando sólo pérdidas inerciales diferentes entre los diferentes cuerpos porosos. Finalmente, se comparan las velocidades obtenidas en cada simulación con datos reales, eligiéndose aquella configuración que arroja mayores ajustes. La metodología planteada pretende poner de manifiesto la importancia de usar con criterio los distintos parámetros propios de la configuración de modelos CFD. This paper presents an introduction about how to model a flow through a porous medium with Computational Fluid Dynamics (CFD). To this end, a case study is proposed by simulating an air current produced by the fan of an air assisted sprayer through a porous medium (vegetation). The work is aimed at adjusting the porosity resistance to the airflow using experimental data. The adjustment assesses three scenarios: one, considering only equal inertial losses between different porous bodies, two, considering both inertial losses and viscous losses and, three, considering only different inertial losses between different porous bodies. Finally, velocities obtained in each simulation are compared with experimental data. The proposed methodology highlights the importance of employing suitable parameters when configuring CFD models.

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Section: Obtención De Los Datos Experimentalesunclassified

Section: Malladounclassified

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Introduciendo la dinámica de fluidos computacional en el análisis de flujos en medio poroso

Salcedo

Bayón

Chueca

2017

Model. Sci. Educ. Learn.

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“…In agrochemical applications on orchards and vineyards, the idea of producing droplets by using nozzles and transporting them to vegetation, by using an air jet generated by a fan, is now the generally accepted method. Some studies [1][2][3][4][5][6] have demonstrated that stream speed strongly influences the effectiveness of spray treatment. If the speed is too low, the distribution of chemicals on vegetation tends to be non-uniform.…”

Section: Introductionmentioning

confidence: 99%

“…On the contrary, if the speed is too high, the leaves align with the air stream, and much of the spray is not captured by the vegetation. Spray drift increases with velocity until approximately 50% of the spray does not land on the vegetation [3,4] and, consequently, causes both economic loss and environmental pollution.…”

Section: Introductionmentioning

confidence: 99%

An Approximate Analytic Solution to a Non-Linear ODE for Air Jet Velocity Decay through Tree Crops Using Piecewise Linear Emulations and Rectangle Functions

Friso

2019

Applied Sciences

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Featured Application: to protect orchards and vineyards from pests, the correct speed of air that carries the agrochemical drops in the canopy is very important. Too slow an air jet compromises the uniformity of spray deposition, while an excessive air speed leads to significant loss of agrochemicals in the environment (≥50%). The present work proposes a mathematical tool to develop a self-regulation system for the air-fans of orchard sprayers. Abstract:The velocity of air that crosses the canopy of tree crops when using orchard sprayers is a variable that affects pesticide dispersion in the environment. Therefore, having an equation to describe air velocity decay through the canopy is of interest. It was necessary to start from a more general non-linear ordinary differential equation (ODE) obtained from the momentum theorem. After approximating the non-linearity with some piecewise linear terms, analytic solutions were found. Subsequently, to obtain a single equation for velocity decay, a combination of these solutions was proposed by using rectangle functions formed through the hyperbolic tangent function. This single equation was assessed in comparison to the experimental value obtained on a vineyard row by measuring the air velocity at exit of canopy. The results have shown good correspondence, with a mean relative error of 6.6%; moreover, there was no significant difference. To simplify, a combination of only two linearized solutions was also proposed. Again, there was no significant difference between the experimental value and the predicted one, but the mean relative error between the two equations was 3.6%.

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Eulerian–Lagrangian model of the behaviour of droplets produced by an air-assisted sprayer in a citrus orchard

Salcedo

Vallet

Granell

et al. 2017

Biosystems Engineering

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During pesticide applications to citrus trees using air-assisted (airblast) sprayers, only a proportion of the volume emitted reaches the vegetation and the rest is lost through drift, evaporation, etc. These losses can be hazardous for the environment. Knowing the characteristics of droplets within the turbulent currents around the canopy could improve the application efficiency. In a previous study, a 2D computational fluid dynamics (CFD) model was used to simulate the effect of a citrus canopy on the airflow from an airassisted sprayer was developed and validated. It considered the first element of the tree canopy as a solid body instead of a porous one. The aim of this study was to analyse the behaviour of the droplets for pesticide applications on citrus by means of an Eulerian-Lagrangian CFD model. It simulated both the air current from the sprayer fan and the wind and the behaviour of the droplets sprayed. Distance, height, velocity, Reynolds number, temperature, geometric and volumetric diameters at different times were obtained. With these parameters, new variables related to the kinetics and evaporation droplets were calculated. Simulation results estimated that 44% of the total sprayed volume reached the target tree, 28% reached adjacent trees, 20% was deposited on the ground and 8% was lost as atmospheric drift. The results largely matched an experimental mass balance carried out under similar conditions. The proposed model appears to be an appropriate tool for simulating treatments with air-assisted sprayers operating in citrus orchards.

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Design and validation of a 2D CFD model of the airflow produced by an airblast sprayer during pesticide treatments of citrus

Abstract: ElsevierSalcedo Cidoncha, R.; Granell Ruiz, R.; Palau-Salvador, G.; Vallet, A.; Garcerá, C.; Chueca, P.; Moltó, E. (2015). Design proposes and validates a two dimensional CFD model to be applied in citrus tree 19

Cited by 15 publications

References 30 publications

Introduciendo la dinámica de fluidos computacional en el análisis de flujos en medio poroso

Introduciendo la dinámica de fluidos computacional en el análisis de flujos en medio poroso

An Approximate Analytic Solution to a Non-Linear ODE for Air Jet Velocity Decay through Tree Crops Using Piecewise Linear Emulations and Rectangle Functions

Eulerian–Lagrangian model of the behaviour of droplets produced by an air-assisted sprayer in a citrus orchard

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